1. Field of the Invention
The present invention relates generally to luminous power supplies, and more particularly to an improved luminous power supply capable of efficiently operating at high frequencies and low voltages.
2. Background of the Invention
Conventionally, neon lighting tubes have been stimulated by alternating currents at high voltages stepped up from power main currents at frequencies of 50 to 60 hertz. Such low frequencies require large diameter cores in transformers, resulting in heavy weights which often preclude neon lights from being used in remote or difficultly accessed locations.
If made available, lamp driver currents at increased frequencies are equally transformable by decreased diameter transformers. In U.S. Pat. No. 4,742,278 by Iannini, a gas discharge display is energized by current at a frequency of approximately 20 kHz, which is adjustable to vary the portions illuminated along the length of the tube as a function of their capacitances. U.S. Pat. No. 4,843,627 by Stebbins discloses a neon light driven by high (at least 20 kHz) frequency squarewave currents in bursts admitted through gates enabled during the envelopes of pulses whose "width" is modulated in a voltage controlled oscillator (VCO) according to signal input times and voltages. Variable-length envelopes of clock signals are succeeded by fixed-length interruptions, so the resultant "pulse width modulated" waveforms do not have regular periods.
Although suitable electronic switching circuitry has been known for some time, to date no suitable combination of electronics and high frequency transformer has been provided capable of efficiently and reliably driving gas discharge devices such as neon tubes and fluorescent lamps.